Effects of Municipal Compost on Germination and Growth of Tomato Seedlings

Compost has been identified as an alternative chemical fertilizer to increase soil fertility and crop production. In this study the capacity of the compost produced from urban wastes to enhance seedling emergence grown in potting soil was investigated. Four treatments were compared based on the addition of increasing quantities of compost to soil (1:2.5, 1:5, 1:7.5, 1:10 compost to soil ratio, v/v). Physical and chemical analyses of the different mixtures were made. Plant growth, biomass production, macronutrients, micronutrients, and heavy metal contents of plant and soil were determined. The addition of compost increased pH, electrical conductivity (EC) of substrates, and macronutrients (N, P, K, Ca, Mg), micronutrients)Fe, Cu, Mn, Zn, B) and heavy metal (Pb, Ni, Cd, Cr, Co) of plants and substrates. The highest germination, growth rate, shoots and roots dry weights were obtained with the medium prepared by mixing rate of 1:5 compost and soil. The mixture with 1:2.5 rate had the lowest germination and growth of tomato seedling. Both toxic constituents and nutrient imbalances may be responsible for the growth-inhibiting effects of the municipal compost in the treatment. The addition of compost to growth media increased plant nutrient and heavy metal contents of plants. Excess adding of municipal compost to agricultural soil may lead to deleterious effects on crops.